Frangible firing device



Nav. 19, 1963 H. L- DODSON 3,111,089

FRANGIBLEFIRING DEVICE Filed Nov. 21, 1960 INVENTOR. Harcflcl L- D ucfsnn.

United States Patent This invention relates to a novel missile skin surface fuze and more particularly to coating a surface of a conventional missile with a resinous coating and subsequently applying to this coating a printed circuit. The term resinous coating as employed in this invention is intended to embrace resins, resinoids, and plastics.

Surface fuzing requires the producing of a fuzing signal to the warhead of a missile as soon after target impact as possible.

The primary object of this invention, therefore, is to achieve this result by applying a resinous coating to any part or all of the missile skin and subsequently applying, by conventional means well known in the art, to this resinous surface a printed circuit. In this manner, it is possible to create a component which can be utilized as a switch capable of detecting target contact by opening on target impact. Accordingly, as soon as this resincircuit component makes target contact, even by a glancing impact, the structural surface will be deformed and will in turn fracture the resinous coating followed by an interruption of the printed circuit continuity. Employing this feature of switch-opening means in an electrical circuit will enable the circuit to act as a surface fuze to generate its own fuzing signal with controlled rise time, width, and amplitude. The resinous coating chosen must have a controlled degree of brittleness, good dielectric properties, ease of application with an ability to form a strong bond With the base material, and be capable of proper functioning in expected environmental and operating conditions. The electrically conductive printed circuit should have good bonding properties with the resinous coating, have controlled resistance and required degree of brittleness and ease of application.

A further object of this invention is to produce a surface fuze which does not require a direct impact for detonating the warhead, but which requires only that the missile skin be physically deformed sulficiently to fracture the resinous coating thereby interrupting circuit continuity.

These and other objects and advantages will be ap parent from the following detailed description and accompanying drawings in which:

. FIGURE 1 illustrates the forward fuselage section and 1 nosecone of a typical missile;

' detonating circuit.

3,111,089 Patented Nov. 19, 1963 Referring now to the drawings and more particularly to FIGURES l, 2 and 3 thereof, there is illustrated the forward portion of a missile generally designated by A and comprising a skin portion 10 having on its interior surface a resinous coating 12. Applied to resinous coating 12 by conventional methods is a printed circuit 14 terminating in circuit connectors 16 connected to warhead 11 and which extend through the missile skin in order to facilitate missile check-out for that portion of the circuitry. It will be understood that connectors 16 are properly insulated from conductive portions of the missile structure. It will be further understood that the resinous coating and its related printed circuitry can just as easily be applied to the exterior of the missile skin, if desired.

The conductive circuit 14 is separated from missile skin 10 by a predetermined thickness of a resinous coating 12, it being apparent, in light of this disclosure, that the sensitivity of this device can be regulated to some degree by this feature of coating thickness, i.e., the thinner the coating the more sensitive it is to fracturing. When a resin-circuit combination has been determined which will meet the required needs of a particular application, insofar as brittleness characteristics are concerned, any deformation by target impact of the missile skin sensitized by this resin-circuit combination, will rupture the resinous surface and accordingly interrupt circuit continuity. The circuit interruption thus obtained is used to generate a transient pulse that will detonate a warhead. The energizing circuit, schematically illustrated in FIGURE 5, shows by way of example, a typical arrangement for accomplishing the detonation wherein such circuit comprises a source of potential P, a switch S slosed prior to launching, a resistor R, a gas-filled diode D, and warhead E. Short-circuit x-y depicts what in actuality is printed circuit 14 whereby from the time switch S is closed until impact, only that portion of the circuit comprised of P, S, R, x and y is energized. At impact, xy becomes interrupted thereby allowing electrical flow from R to D and E resulting in the detonating of the warhead.

It is to be understood of course that the missile skin can be sensitized in its entirety by 360 degree coverage throughout its entire length or only in a selected portion or portions thereof. Range test have revealed that this type of fuzing device can be varied to give a fuzing signal from a few microseconds to several hundred microseconds, depending on the particular application.

It is to be noted that in the embodiment illustrated, Very little of the internal volume of the missile is occupied by this device and the weight factor can be evenly distributed. As a measure of further environmental protec tion, a protective resinous coating 12a, FIG. 4, can be applied over the circuit and base coating Without affecting the operation of this device.

While the foregoing particularly describes the preferred embodiments of my invention, it is obvious that many modifications and variations in the details of construction, combination, and arrangement of parts may be resorted to without departing from the spirit of the invention and scope of the appended claim.

What I claim as new and useful is:

A surface fuze for a missile including an external skin structure, a warhead and a detonating circuit, said skin structure having exterior and interior surfaces; said fuze 55 comprising a coating of frangible dielestric material covering the interior surface of said skin structure; a conductive circuit printed on the interior surface of said coating, said conductive circuit being disposed in a serially repeating longitudinal pattern around the entire forward interior surface of said coating and a pair of terminals connected to said conductive circuit for electrically connecting said conductive circuit with the detonating circuit, said dielectric coating and said conductive circuit fracturing upon an impact on said skin to permit the detonating circuit to fire the Warhead.

References Cited in the file of this patent UNITED STATES PATENTS Winkley June 30, 1925 Bleakney et a1. July 12, 1955 Ward May 20, 1958 Perret May 19, 1959 

